Circuit arrangement for neon lamps in telephone systems



March 12, 1935. K. FABER 1,993,880

CIRCUIT ARRANGEMENT FOR NEON LAMPS -IN TELEPHONE SYSTEMS Filed April 81932 Karl Faber Patented Mar. 12, 1935 UNITED STATES PATENT OFFICEcmcurr ARRANGEMENT FOR NEON LAMPS IN-TELEPHONE SYSTEMS many 'Application April 8, 1932, Serial No. 604,091

In Germany April 9, 1931 4 Claims.

This invention relates to a circuit arrangement for neon lampsparticularly of the type which 'are lighted by an additional voltage forthe purpose of causing electromagnetic operations in tele- 5 phonesystems. a

In known arrangements of this type, for telephone systems, a directpotential is used as an auxiliary voltage and permanently applied to theneon lamp. For signalling purposes, the neon l0 lamp is lighted by theadditional voltage applied to it and consequently a relay placed inseries with said lamp is caused to operate. As, however, the strikingvoltage for the ordinarily used neon lamps is so high that the lampcannot be lighted 13 by the additional signal potential when only thepotential from the existing battery in a telephone exchange is used asan auxiliary potential, an additional batteryhas heretofore beenrequired to attain the striking potential.

This device, according to the invention, eliminates the supplementaryexchange battery by generating induced impulses in the secondary windingof a transformer, with-the aid of an interrupt-- er utilizing thebattery current or with the aid of the current of an existingalternating current source of supply, said impulses, upon rectification,producing an auxiliary potential for raising the battery potential tothe required voltage.

Fig. 1 shows the invention applied to an impulse repeater for a voicefrequency dialling system. The line L may be a toll line whichterminates in an automatic switch by means of'which it can beselectivelyconnected to other lines. The switch forms no part of theinvention and therefore only the motor magnet M is shown. The switch iscontrolled by voice frequency impulses transmitted over the lineL andrepeated to the magnet M of the switch by the relay R of the repeater.

Figs2 shows the invention applied to a neon tube oscillator, which maybe used for generating tone currents used for various purposes intelephone systems. As shown in the drawing the os-- the transformer Trl,and relay R. If the primary circuit of the transformer Trl is now intermittently opened and closed by the interrupter U1, induced impulses ofalternate direction are generated in windings II and III of saidtransformer. The induced impulses of the one direction are transmittedto the neon lamp by the rectifier G1 and impulses of the other directionare likewise transmitted by the rectifier G2 with the result that thesepotentials are addedto the voltage applied to the lamp from the batteryover the above-mentioned circuit. The voltage of the I battery and theratio of the transformer is such that the total voltage of the lampapproximates the lighting voltage of said lamp. Although in Fig. 1 thebattery Btl is shown in two difierent circuits and in Fig. 2 the batteryBt2 is shown at two places, it should be understood that there is onlyone.battery Btl in Fig. 1, for instance, and only one battery Bt2 inFig. 2. The batteries are separately shown in order to overcome thenecessity of showing separate leads extending from the battery to eachof the two circuits, and it is believed that the disclosure issimplified thereby.

When voice frequency alternating current impulses are transmitted overline L, said impulses are transmitted to the transformer Tr2 over thetransformer T13 and over an oscillating circuit of a type known forvoice frequency signal receivers which is tuned to the signal frequency.The impulses are therefore superimposed on the potential applied to theneon lamp and in this manner cause the lamp to be intermittentlylighted. If the frequency of the interruptions and consequently thefrequency of the impulses induced in the neon lamp circuit by theinterrupter is so calculated that the periods during which the voltagedrops below the lighting voltage of the lamp ,are of such a shortduration that the lamp will not be extinguished, an uninterrupted flowof current passes through the relay during each received voice frequencyimpulse. The relay is, therefore, effectively energized once for eachimpulse, and by the closing of its contact 1' each time, it completesthe circuit of the magnet M a number of times, thereby setting theswitchto select the desired line.

The device according to Fig. 2 lows:

In a manner similar to that described in the preceding example thevoltage from the battery BT2 is applied to the neon lamp GL2, on'the onehand, over winding I of the transformer 'Ir5 and, on the other hand,over the rectifier -(9:3, winding operates as fol- II of the transformerTM and the variable resistance W1. A condenser K, charged by the batteryvoltage is, in addition, arranged in parallel with the lamp and thewinding I of the transformer Tr5. I

The induced impulses generated by the interrupter, after rectification,increase the constant battery voltage. This results in a chargingcurrent passing through the condenser K until the potential applied tothe condenser has reached the lighting voltage for the neon lamp. Atthis moment the condenser is discharged over the neon lamp and winding Iof the transformer Tr5. This a discharge causes the potential at thecondenser to drop below the lighting voltage for the lamp so that it isextinguished and the cycle is repeated.

The current alterations repeatedly produced in this manner in winding Iof the transformer Tr5 set up induced impulses in the secondary circuitof the transformer which, in turn, influence the telephone T, causingthe diaphragm of said telephone to oscillate with the result that tonesare audible in the telephone.

It is possible to control the charge period of the condenser andconsequently also the frequency of the discharges by varying theresistance Wi. In this manner the pitch of the tone produced in.

the telephone may be controlled by the resistance.

Instead of generating the auxiliary potential, required to raise thebattery voltage, by means of the interrupter U2, the ringing currentsource of supply in the exchange maybe used for this purpose, in whichcase it is connected to winding I of the transformer T14. What isclaimed is:

1. In an impulse repeater, two branch circuits having a common portionincluding a neon tube connected in series with a relay, a battery, andthe secondary of a transformer, a filter circuit connected to theprimary of said transformer, 'a rectifier connected in each branch ofsaid neon tube circuit, asecond transformer with its secondary connectedto said filter circuit, an incoming line with the primary of said secondtransformer connected across it, a third transformer 'with its secondaryconnected'in said branch circuits, an interrupter connected in serieswith a battery and the primary of said third transformer, meanscontrolled by said interrupter and, said third transformer for raisingthe circuit voltage to approximately the flash voltage of said neontube, means for transmitting voice frequency impulses over said incomingline, said impulses causing said neon tube to strike allowing said relayto operate, and means controlled by said relay for repeating saidimpulses.

2. In an impulse repeater, two branch circuits flash voltage of saidneon tube, means contained in said circuit for allowing current to passonly in one direction through said neon tube, an incoming line, meansfor inductively connecting said neon tube circuit across said incomingline, means for transmitting voice frequency impulses over said incomingline, said impulses causing said neon tube to strike and operate saidrelay, and means controlled by said relay for repeating said impulses.

3. In an impulse repeater, two branch circuits with a common portionincluding a neon tube in series with a relay and a battery, the voltageof said battery being below striking voltage of said neon tube, atransformer with its-secondary connected to the branch circuits, meansfor impressing a pulsating current on the primary of said transformercausing an induced voltage in said branch circuits, means in saidbranches for allowing current to flow in only one direction through saidneon tube, said induced voltage when added to said battery voltageraising the latter sumciently to .approach the striking voltage of saidneon tube, an incoming line, means for inductively connecting said neontube circuit across said incoming line, means for transmitting voicefrequency impulses over said incoming line, said impulses causing saidneon tube to strike and operate said relay, and means, controlled bysaid relay for repeating said impulses.

4. In an impulse repeater, two branch circuits with a common portionincluding a neon tube connected in series with a relay and a battery, arectifier connected in each branch of said circult, a transformer withits secondary connected to said branch circuits, means including aninterrupter connected inseries with a battery and the

